Presently, the environment problems and the oil wasteful consumption caused by the traffic congestion become serious in our country and further the cost for transportation is increased in geometrical. Thus, the optimization in traffic flow is earnestly required. Even though the construction of roads may be the substantial solution for traffic problem, it requires the tremendous cost. Accordingly, it is desirable to find a method for efficiently using the roads currently provided.
There is disclosed a conventional method for providing an image-based traffic information, which introduces nodes. For this method, bit-map based images are stored in the user terminal and the node database must be also stored in the user terminal. The transmitting side (or server) sends the traffic information in text along with the corresponding node numbers. Also, the receiving side (or user terminal) updates the node database in accordance with the received traffic information and node numbers and generates an image in accordance with the content of node database. However, since the node database requires a large quantity of memory and the processing for generation of the image also requires a relatively large number of operations, the user terminal is very complex and thus the cost for manufacturing becomes high, resulting in preventing the method from being popularized. Also, it is difficult that the bitmap-based images of the user terminal are replaced with another one as necessary since the size of the images are too big to be transmitted. Further, adding and/or deleting of a node may need to change the composition of the node database and thus it is not convenient for both a user and an information provider. In summary, the conventional method is prodigal.
In addition, the conventional method has the problem that, when the number of the nodes is large, it is difficult to assign node numbers to respective roads and to maintain the standard therefor.
Also, other conventional methods for transmitting the traffic information in text or in voice type are disclosed. The former method has the problem that a large quantity of data transmission should be made. The latter method has the problem that a relatively long time is required for user to acquire an interested traffic information and this type of traffic information is not easy to understand overall traffic situation.